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Automation

The endless debate about how fully automated cars would change our cities often starts with the assumption that we will have fully automated cars soon. We imagine that we’ll all be riding around in totally automated taxis, whose lack of a driver will make them cheap.

This is the essence of the “driverless cars will replace transit” fantasy. I’ve arguedmanytimesthat this idea is geometrically incoherent in dense cities, because regardless of automation there isn’t enough room to move people from big transit vehicles into small ones.

But it’s also important to ask: How soon is this truly driverless vehicle really coming?

Levels of Automation

Here is the standard 1-5 scale, by SAE International, that everybody uses to talk about this. Level 1 technology is available now, but the kind of automation that totally eliminates a driver, thus transforming the economics of all hired transportation, comes only at Level 5.

Six levels of automation. Videantis. http://www.videantis.com/what-are-all-these-automotive-cameras-doing.html

Most experts seem to agree we will soon have Level 2, enhanced driver-assistance that shifts the driver to more of a monitoring role, but that the journey to Level 5, actually eliminating the driver, is a long one that has only begun.

Steven E Shladover, from the PATH program at UC Berkeley, has been thinking about vehicle technology for decades. In his excellent (and tragically paywalled) piece for Scientific American this June, he noted some of the reasons why full automation is so hard, and requires solving problems that are not just technological.

A fully automated vehicle needs to be able to do the right thing any situation, and handle its own equipment failures. In big airplanes, this is achieved only through multiple redundant systems that make the product massively expensive. Nobody knows how to scale an airliner’s level of redundancy to an affordable mass-market vehicle.

Crossing the Ravine of Distraction at Level 3

The biggest barrier to full Level 5 automation may also be a reason to leap to it prematurely. It’s human reaction time at the intermediate levels of automation. Shladover:

The prospects for level three automation are clouded, too, because of the very real problem of recapturing the attention, in an emergency, of a driver who has zoned out while watching the scenery go by or, worse, who has fallen asleep. I have heard representatives from some automakers say that this is such a hard problem that they simply will not attempt level three. Outside of traffic jam assistants that take over in stop and go traffic, where speeds are so low that a worst case collision would be a fender bender, it is conceivable that level three automation will never happen. [Emphasis added.]

Anyone examining their own experience will see that this is a big problem, and that it’s not a technological problem.

To make this more vivid, let’s stop and think what the opposite of automation is. It’s an old mid-century car, maybe my parents’ 1962 International Scout, a tough precursor to today’s SUVs. The primitive suspension pounded your body with the textures of the road. Your hand on the stick-shift felt the movement of the gears. When something shoved back against your attempt to turn, the steering wheel sent the shove right up your arms. To stop fast, you had to pound the brakes with your weight. Nothing pretended to protect you from the weather. With all this vivid input flowing into you, demanding constant decisions, you would never fall asleep at the wheel, or be tempted to look at the newspaper on your seat. Driving was hard, but often ecstatic. When power steering and automatic transmissions came along, my elders agreed that by reducing the level of effort and stimulation, these inventions made driving harder to focus on.

The journey from here to Level 3 looks just like the journey from the Scout to here. It’s the same straight-line path from vividness toward tedium, from control to passivity. It ends at a faintly ridiculous extreme: you sit there, unstimulated and with nothing to do, but you must still pay attention. We could reach a point where the only safe “drivers” are people with years of meditation training, since nothing else prepares you for that situation. And all that training would be expensive, pushing drivers’ wages up!

At Level 3, Forward or Back?

If the Level 3 problem is as hard as it looks, how will we respond? Tech-optimists will see this as a reason to rush even faster to Level 5, maybe prematurely. But many people who get a taste of Level 3 will be keen to stop at Level 2, where they still feel like they’re in control. Level 3 accidents, caused by human inattention but easily blamed on the technology, would inflame both sides in this debate.

At that point, will the reason to go forward be safety? We don’t know, because we don’t know what the impact of Level 2 will be on fatality rates. Maybe they will have improved so drastically that Level 5 doesn’t offer that much more, or at least not enough more to make the public ready to accept the loss of control at that level.

So the other issue will be the liberation of labor, especially professional drivers. All the dreams of driverless taxis, for example, require getting all the way to Level 5. Maybe it will happen, starting with fleets, but the question of whether you can jump over the ravine of distraction at Level 3, and land all the way at Level 5, is an open one.

Are we sure driverless vehicles will be cheap and abundant soon? I have no idea, and nobody else does either, but the path does not look easy.

Automated Transit Is Easier!

So what does this all mean for transit? You read it here first: Full automation of transit is much easier than automation of cars. (If it’s impossible, that’s only because driverless cars turn out to be impossible.) Shladover:

And yet we will see highly automated cars [vehicles?] soon, probably within the coming decade. Nearly every big automaker and many information technology companies are devoting serious resources to level four automation: fully automated driving, restricted to specific environments, that does not rely on a fallible human for backup. When you limit the situations in which automated vehicle systems must operate, you greatly increase their feasibility. [Emphasis added.]

High-ridership fixed route transit vehicles are perfect examples of this possibility. They run on pre-set paths in a narrow range of situations. In fact, the busier they are, the more money we should spend to make these situations narrower: exclusive lanes, automated stopping and fare collection, weather protection technologies, and potentially limits on lateral motion, up to and including rail. Unlike vehicles that could go anywhere, automated transit vehicles don’t need a map of absolutely everywhere. All of these things make transit automation easier. In effect, transit is a case where you can get full automation with Level 4 technology.

I am not making light of the considerable challenge of managing the impact of the transformation of the workforce wrought by automation. I am very concerned about those impacts. But the effect of automation on work is an issue in many fields, and when it becomes critical we will find a collective solution. Smart people are thinking about it.

Takeaways:

Full automation of any kind, going anywhere, the goal that replaces most human labor, is quite a ways off and requires overcoming several obstacles that nobody has cracked yet. It may not be possible.

Driving a partially automated vehicle may be harder than driving a vehicle today, because the distraction problem gets worse. This may increase the skill level of the labor required, and thus the labor cost.

But the distraction problem with partial automation may also cause a premature rush to full automation, plus a strong movement to stop at Level 2.

Technologically and spatially, high-ridership fixed-route transit is much more easily automated than any other vehicle under discussion today, because it operates in such limited situations. Fully automated rail transit, in regular service, is over 30 years old. Driverless buses are under development and present especially promising options especially in fixed rights of way.

If driverless transit were ever achieved, the explosive growth in transit abundance would be extraordinary, because labor cost is the main limiting factor today. This vast increase transit would mean cities could grow denser with less traffic, putting more opportunities within a shorter travel time for everyone.

An important belated update from the world of ridesharing – Uber is now testing a feature they are calling "Suggested Pickup Points", which directs customers to walk to nearby locations that are easier for their drivers to reach, saving time for both the driver and (in the case of UberPool) for other passengers on board. Lyft takes this even further, offering discounted rides on its Lyft Line service for people who come to meet it.

You may be familiar with an identical concept in the public transit industry, called a "stop" or "station" — a location near to destinations, but maybe not at their front door, that is cost-effective for a transit vehicle to reach. This saves the driver the time it takes to drive to the precise preferred location of each passenger, which is especially crucial if there are other passengers on board whose travel time is also valuable. (It also encourages a bit of walking where that's easy to do, which is good for you!)

This new feature illustrates how a demand-responsive service like UberPool can evolve to resemble the very fixed route bus that it often pretends to be supplanting, particularly when serving high-volume markets. Discounts for walking to a pickup point make perfect sense, for the same reason that fixed route transit should be even cheaper; the customer is taking on inconvenience in return for a more efficient transit service.

These moves show these companies recognizing the geometric logic of rigid, fixed transit: that when you connect places where many people want to go together, along a fast, direct path, the resulting service is both efficient to provide and useful to vast numbers of people.

Flexible transit sounds like it's more responsive to our needs as customers, but if you want it to be affordable it has to be efficient. The vehicle that comes to your door is intrinsically a low-efficiency concept when efficiency means "passengers/driver hour", as it will so long as the cost of service is mostly labor cost.

That's why, for decades, transit agencies have sometimes deployed flexible services in low-demand but growing markets but then replaced them with fixed routes as demand grew beyond what the low capacity of flexible services could handle. Transit agencies also know about "fixed stop Dial-a-Ride", which is the specific phase of this inevitable evolution that Uber and Lyft are exploring now.

The cool kids at Uber and Lyft are showing that for all their pretense of having invented something new, they live in the same geometric and economic space as their ancestors, and will evolve the same solutions that worked in the past. Data is cool, and technology is cool, and enraptured high-paying customers are very cool, but none of that changes the facts of space, biology and economics, ever.

Will driverless cars change all this? Not if we also have driverless buses. In that case, the math and geometry, and the nature of efficiency, will be largely the same.

Part 2 of my letter from Luca Guala, of the Italian consulting firm Mobility Thinklab. (Part 1, on personal rapid transit, is here.)

Last summer, we tested driverless minibuses along a route of 1.3 km on a pedestrianized boulevard in Oristano, a small town in Italy. The idea was to test driverless vehicles mixed with traffic.

Why minibuses and not taxis? Firstly, because it is much simpler to teach a robot to follow a fixed route, rather than teach it to go anywhere the passengers want to go. Such a system is already operational in Rotterdam (2getthere.eu/projects/rivium/) and it works well, but it has one drawback: the tracks are segregated and they represent an ugly severance in the urban tissue.

But if the vehicles are allowed to run with cars cyclists and pedestrians, a public transport route can be “adapted” with unobtrusive measures to accept driverless vehicles, and the people sharing the road will quickly learn to live with them. The main problem here was not technical, as legal.

Hence the idea of testing similar vehicles in an open field mixed with pedestrians. The first test we did had mixed results, the second test that will be done in La Rochelle, France this winter will take advantage of all that we learned in Oristano.

So what did I learn from all of this? That driverless cars very likely have a bright future, but cars they will always be. They may be able to go and park themselves out of harm’s way, they may be able to do more trips per day, but they will still need a 10 ft wide lane to move a flow of 3600 persons per hour. In fact, the advantage of robotic drivers in an extra-urban setting may be very interesting, but their advantages completely fade away in an urban street, where the frequent obstacles and interruptions will make robots provide a performance that will be equal, or worse than, that of a human driver, at least in terms of capacity and density.

True, they will be safer (especially because the liability for accidents will be borne upon the builder) and a robotic traffic will be less prone to congestion (I envision robotic cars marching orderly like robots, packed at 1.5 second intervals, while their occupants fume wishing they could take the wheel perfectly aware, but not at all convinced that their robocars are more efficient drivers than they are – or worse, they DO take the wheel overriding the … robots!), but I do not expect driverless cars to dramatically increase the capacity of a lane to transport persons.

Driverless buses, on the other hand offer an interesting feature: the human driver is no longer needed, removing an important cost and several constraints. This allows them to serve efficiently and economically low-demand routes and time bands, while allowing [agencies] to concentrate the number of manned buses on high demand routes at little added cost.

I take all this automation talk with a grain of salt still, as I don't think we've begun to explore the human response to it. But Luca is right about the key point: driverless buses are a much easier problem than driverless cars, and their space-efficiency will continue to be crucial in busy corridors where even driverless cars will add up to gridlock.

Luca's last paragraph suggests that driverless buses will start with smaller vehicles in simpler situations, which is a possibility. But of course, once the concept is proven, the economics of driverlessness will create pressure to bring the technology to big buses. The same logic is also driving the movement to run fully-grade-separated without drivers, on the model of Vancouver, Dubai, and Paris. The logic of driverless trains is easy: with automated train controls systems there is really not much for a driver to do in non-emergency situations, and these cities have found that those tasks are easily automated. We are all used to small systems of this type, because we encounter them in large airports. The driverless bus in traffic is a harder problem, but we will have solved all of those problems if we ever develop driverless cars. In fact, the problem of the driverless bus, which never goes into alleys or minor streets, should be considerably easier, since navigation turns out to be one of the biggest challenges for the driverless car.

Note also that the challenge of planning for driverless cars is not in envisioning a utopia where they have complete dominion over the street. The future must be evolved, which means that we must plan for the interim state in which some cares are driverless and most aren't. That is a situation where driverless buses could thrive, because they will be competing with something that — in terms of poor capacity utilization — resembles today's traffic on major streets, not a world optimized for the driverless car.

As Luca indicates, we know what the problem with driverless transit will be: long fights with labor unions who feel entitled to cradle-to-grave security in a single job. It will be one more kind of automation that requires people to retrain and to participate in a more complex and competitive economy. In an ideal system, many drivers would be replaced by support jobs such as fare inspectors and roving problem-solvers; as on Vancouver's SkyTrain. This seems to be what Luca is envisioning when he speaks of the continued need for "manned" services.

But the real result of massively abundant transit — which is the real point of the large driverless bus – will be massively more opportunity for all kinds of innovation and commerce to happen in a city, unconstrained by the limits of car-based congestion. That's a wrenching change, and I am as adamant as anyone about the need to protect workers from exploitation. But in the long run, over a generation or two, the outcome will more interesting jobs for everyone. Bus drivers shouldn't encourage their children to go into the same profession with the same expectations, but that's true of many jobs — perhaps even most jobs — in this rapidly changing world.

Antonio Loro is an urban planner with a particular interest in transportation innovations. In research conducted for TransLink and Metrolinx, he investigated the potential impacts of vehicle automation technologies. The views expressed in this article are those of the author and do not necessarily represent the views of, and should not be attributed to, TransLink or Metrolinx.

Vehicle automation is increasingly showing up on the radar of urban planning and transportation planning professionals. Technologies are developing rapidly, and some newsstoriesreport that fully self-driving cars are just a few years away. It’s tempting to envision automation ushering in a bold new era in urban transportation, where driverless cars whisk passengers between destinations safely and conveniently, use roads with great efficiency, and make public transit as we know it obsolete.

However, a closer look at vehicle automation reveals a more nuanced picture of the future. Automation capable of replacing human drivers in any situation may be many years away from the market. The traffic flow improvements enabled by automation will be limited in several ways. Buses and other forms of public transit will still be needed to efficiently move large numbers of travelers around cities. And various forms of automation in buses could enable major improvements in service.

The last two points have come up on this blog before (here, here and here), but since there are a variety of opinions on the implications of automation for transit, it’s useful to dig a bit deeper into these issues and take a critical look at when various forms of automation will arrive, how automation will affect traffic flow, and how it will affect travel behaviour. This post will delve into those questions to shed a bit more light on what automation means for the future of public transit.

According to some, vehicles that can drive themselves anywhere, anytime, without any human intervention – described as “Level 4” vehicles by the National Highway Traffic Safety Administration (NHTSA) – are just around the corner. In 2012, Google co-founder Sergey Brin said of their famous self-driving car: “you can count on one hand the number of years until ordinary people can experience this.” Many others have made bullish predictions. For example, the market research firm ABI Research foresees Level 4 cars on the roads by around 2020, and panelists at the Society of Automotive Engineers (SAE) 2013 World Congress predicted arrival between 2020 and 2025.

On the other hand, some point to a number of challenges that suggest Level 4 will emerge further down the road, perhaps not for several decades. Steven Shladover of the California Partners for Advanced Transportation Technology, a leading expert on vehicle automation, argues that Level 4 will be much more technically difficult to achieve than many optimists acknowledge (see Vol. 7, No. 3 here). According to Shladover, huge advances in technology would be needed to progress to systems capable of driving safely in the vast range of complex and unpredictable situations that arise on roads. In addition, such systems would have to be far more reliable than products like laptops or mobile phones, and extensive – and expensive – testing will be needed to prove reliability. While Google’s vehicles have driven long distances in testing – over 500,000 miles as of late 2013 – and have not caused any crashes while in automated mode, Shladover points out that this proves very little because their vehicles are monitored by drivers who take over when risky or challenging situations arise.

Legal and liability issues could also delay the emergence of Level 4 vehicles. A few American jurisdictions now explicitly allow automated vehicles on public roads for testing, and Bryant Walker Smith, a leading authority on the legal dimensions of vehicle automation, has found that automated vehicles are “probably” legal in the US; however, he also cautions that their adoption may be slowed by current laws. Laws will have to be clarified before Level 4 vehicles hit the mass market in the US and in other countries. Liability for crashes could also be a thorny question. If a human isn’t driving, presumably blame would shift to the manufacturer, or perhaps a supplier of system components, or a computer programmer. Resolving these issues could stall the emergence of automation.

While there is dispute as to when Level 4 vehicles will be on the road, most in the field agree that more limited forms of automation are coming soon. Some are already here. For example, Mercedes S-Class vehicles can simultaneously control speed and steering when road and traffic conditions allow, though the driver must continuously monitor the road. This is just shy of “Level 2” automation, since Mercedes’ system also requires the driver to keep their hands on the wheel. Numerous other vehicle manufacturers are developing advanced technologies that promise to take over driving duties, at least some of the time, on some roads. As technologies advance, “Level 3” vehicles could be on the market by 2020 to 2025, according to most experts. These vehicles would allow drivers to forget about monitoring the road and instead read or watch a movie, with the caveat that when the automated system is out of its depth, it would ask the driver to take over. (The takeover time is a matter of debate – anywhere from several seconds to several minutes has been suggested.)

Automation could be a boon for safety – or it could create new problems. On the plus side, it appears that crash avoidance systems already on the market may be effective. Of course, as machines take over more of the responsibility of driving, safety will only improve if the machines are in fact less fallible than humans. This might seem an easy task, considering the foibles of humans, but it’s worth remembering that some automation experts believe otherwise. And where driving is shared between human and machine, the safety impacts are especially open to question. A driver in a Level 2 vehicle might fail to continuously monitor the road, or a driver in a Level 3 vehicle could be engrossed in their movie and fail to take over control quickly enough when requested. In either case, automation could actually decrease safety.

After safety, one of the biggest selling points of vehicle automation is its potential for improving traffic flow, especially through increased road capacity. With their slow reaction times, human drivers can’t safely follow other vehicles closely, so even at maximum capacity, around 90 percent of the length of a freeway lane is empty. If machines could react quickly enough, road capacity would increase enormously. Some studies appear to suggest huge increases are in fact possible – for example, one study estimates that capacity would almost quadruple, and another finds quintupled capacity. However, their calculations consider endless streams of densely-packed vehicles. More realistic estimates assume that several vehicles, say four to twenty, would follow each other in tightly packed groups or “platoons”, with each group separated from the next by a large gap. These interplatoon gaps would provide safety and allow vehicles to change lanes and enter and exit the freeway. Studies that account for these gaps estimate that automation would increase capacity in the range of 50 to 100 percent (for examples, see here and here).

While the more realistic estimates of capacity increases are still very impressive, there are a number of caveats. First, short headways are possible only when automated vehicles are equipped with V2V, or vehicle-to-vehicle communication. Vehicles that rely completely on on-board sensors – such as the Google self-driving car, in its current form – cannot react quickly enough to the movements of other vehicles, so they would enable relatively small capacity increases. A second caveat: large capacity increases would come only when automated cars dominate the road. Studies have found that when fewer than 30 to 40 percent of vehicles on the road are capable of platooning, there would be little effect on capacity, and large increases would come only after the proportion of equipped vehicles exceeds 60 to 85 percent (e.g., see here). This is important, since new vehicle technologies will take some time to become commonplace. Imagine that as soon as automated vehicles hit the market, every new vehicle purchased is automated: it would then take two decades for automated vehicles to account for around 90 percent of vehicles on the road. If the rate of adoption is more realistic, but still rapid, it would take three decades or more before automated vehicles make possible large road capacity increases. A third major caveat: platooning is only feasible on freeways. Changing lanes, stopping at red lights, making left turns, parallel parking, stopping for pedestrians – such manoeuvres would make platooning impractical on city streets.

For city streets, however, there is the prospect of using automation to improve flows at intersections by coordinating vehicle movements. A good example is the “reservation-based” intersection, where there are no stop lights or stop signs – instead, cars equipped with V2I (vehicle-to-infrastructure communications) technology “call ahead” to a roadside computer that orchestrates the movements of vehicles and assigns time and space slots for vehicles to cross the intersection. Simulations show such an intersection could move almost as much vehicle traffic as an overpass – but so far, simulations haven’t included pedestrians and cyclists. Accommodating these road users in a reservation-based intersection would require signals with sufficiently long cycles, so capacity increases would be limited.

Vehicle automation would also bring a very direct impact: reduced or eliminated labour in driving. Time spent traveling in Level 2 vehicles could be less stressful, and could become more productive and enjoyable in Level 3 and especially in Level 4 vehicles. Profound changes in travel behaviour would result. As people increasingly let their robot chauffeurs deal with road congestion and other hassles of driving, travel by motor vehicle would become more attractive. Trips would tend to be longer and more frequent and travel at peak times would increase. Trip routes would also tend to make greater use of freeways with Level 2 and 3 vehicles, since it is primarily on these roads that the vehicles will be able to operate in automated mode.

These induced demand effects would tend to increase road congestion. Freeways would be the exception – if platooning-capable technology becomes widespread, freeway capacity would increase and congestion would drop. That is, until the surplus capacity is taken up by the “triple convergence” of mode shifts, route changes, and change of time of day of travel. However, the increase in freeway traffic would be constrained by capacity limitations on the rest of the road network – as freeway travel increases, new bottlenecks would form on streets near freeway entrances and exits, where automation does not boost capacity, thus restricting the volume of traffic that can access the freeway.

The upshot of the above observations on the capacity effects of automation is that even when the potential freeway capacity increases enabled by platooning are fully realized, automated cars would nevertheless be able to carry far fewer people than bus or rail on a given right-of-way. And, as mentioned, capacities on streets will be largely unaffected. Because the capacity improvements made possible by automation would be limited, we will still need buses and trains when space is in short supply and we need to transport large numbers of people. Larger vehicles will still fit a lot more people into a given length and width of right-of-way than platoons of small vehicles will be able to carry. As Jarrett would say, it’s a simple fact of geometry.

So, vehicle automation will not render large transit vehicles obsolete. On the contrary, it could enable significant improvements in bus service and increases in ridership. Automated steering enables bus operation at speed in narrow busways, which reduces infrastructure and land costs. It also enables precise docking at passenger platforms, which improves passenger accessibility and reduces dwell times. Automated control of speed enables bus platooning, allowing buses to effectively act like trains. Automation can be taken further yet: a driver in a lead bus can lead a platoon of driverless buses, thus providing high capacity with low labour costs. Similarly, individual buses or platoons can operate driverlessly, thus enabling increased frequency with low labour costs. “Dual mode” operation is also possible: imagine a busway where chains of buses leave the city running like a train until they separate at a suburban station, where drivers board and take them onward onto various local routings.

Some of these forms of automation have already been implemented in BRT systems. For example, a system in Las Vegas employed optical sensors to enable precise docking at passenger platforms, BRT buses in Eugene, Oregon used magnetic guidance to facilitate precision docking and lane-keeping in a pilot project, and systems in Paris and Rouen, France, and in Eindhoven, the Netherlands, use various types of guidance systems. While bus platooning and driverless operation have not been deployed so far, these applications could be achieved given sufficient technological advances – or by using a low-tech shortcut. The simple solution is to keep other vehicles or humans out of the way of the automated bus. If buses operate on busways with adequate protection, platooning and driverless operation is possible with existing technology. (Similarly, current driverless train systems are able to operate driverlessly, even with decades-old technology, by virtue of the well-protected guideways they run on.) Developing a vehicle capable of driving itself in the simplified environment of a protected busway is a considerably easier task than developing a vehicle that can drive itself on any road, anytime.

With the arrival of Level 4 automation, driverless buses could operate on the general road network. This would make it possible to operate smaller buses at higher frequencies, since labour costs would no longer constrain frequency. If you shrink driverless buses small enough – and provide demand-responsive service for individual travelers – you end up with driverless taxis. This points to the possibility that public transit service may be more efficiently provided by driverless taxis (or driverless share taxis) in low-density areas, thereby replacing the most unproductive bus services and improving transit productivity overall. (Of course, while automation could boost productivity, even driverless demand-responsive service would still have low productivity where densities are low.)

While it’s a seductive story that driverless cars will transport us to a realm of much improved safety, convenience, and efficient road use – and where public transit has dwindled away – the future is likely to be more complicated. Advanced automation is indeed coming soon, though we might not see Level 4 technologies for a while. Automation could improve safety, though it could also generate new problems. It could also improve road capacity, but the improvements would be limited in several ways. All this suggests that we needn’t worry about (or celebrate) how vehicle automation will make public transit obsolete. Instead, let’s focus on how to use automation to the advantage of public transit.

A recent post of mine on the potential of driverless cars elicited an excellent comment thread. My own response is in the works, but meanwhile, here is one of my longtime mentors, Ron Kilcoyne, on the topic. Ron is the General Manager of Lane Transit District, the transit system covering the Eugene-Springfield area in Oregon.

About three months ago I read one of Jarrett's posts that provided a good explanation as to why self-driving cars will not become the transportation utopia that its promoters envision. I had just returned from the American Public Transportation Association (APTA) Annual meeting and this post provided a needed antidote to sense of depression I was feeling.

During the Conference I heard speaker after speaker wax poetic about the trends that favored significant transit growth. And every time I heard wonderful visions of this transit (and pedestrian and bicycle) nirvana, I kept thinking to myself: but what about self-driving cars? Will they undo the positive trends towards less sprawl, revitalized cities and walkable suburbs? Will we once again become isolated in our pods even at levels unheard of at the height of our past car culture?

The focus of this earlier post (as opposed to the recent one which generated lots of chatter that focused on how we get from today to the self-driving autopia) was the physical limitations that will impede the vision that self-driving cars will replace transit as we know it today. Now being a transit geek all my life (my parents did not drive so I was dependent on transit growing up) and a transit professional for almost 33 years (early in his career Jarrett worked for me) you may think I am not willing to accept change out of fear the buses and trains that I am passionate about will disappear. Maybe a little but my real concerns are far much broader and relate to the social, health and environmental implications of self-driving cars becoming the sole motorized mode.

Evidence keeps piling up that the keys to longevity, good health and happiness lie in social interaction, physical activity and diet. I might add that beauty is also important; both from easy access to nature and in our built environment. Whereas a car centric society has encouraged isolation, less physical activity and ugly sprawl that has also diminished healthy local food production; there are a number of positive trends moving in the opposite direction. The tea party and its paranoia notwithstanding, more and more people value a physical environment that supports sociability, active and public transportation. Will these trends grow or wither? Factors other than self-driving cars may play a role in answering that question but at some point self-driving cars could play a major role in determining how society evolves.

Mark Frohnmayer, who is a member of the Oregon Transportation Commission and owner of a company developing an electric car, presents a PowerPoint to groups interested in his vision of the future of urban transportation. The three components of his vision are electric cars, car sharing and self-driving cars. What I found most memorable from his presentation was his illustration of how a part of Eugene transforms into a green urban utopia as acres of land currently devoted to parking are put to other uses. Peter Calthorpe makes a compelling case as to why electric cars are not the answer to our energy or climate issues and that we will still need urbanism that supports the pedestrian/bicycle/transit modes. Jarrett Walker has likewise presented good evidence as to the physical limitations of self-driving cars in an urban environment. This leaves car sharing as the one component of Mr. Frohnmayer’ s vision that could reduce the amount of land devoted to parking.

I am a big fan of car sharing and believe that its growth can be an essential component of improving the sustainability of our cities and towns. Indeed car sharing is an important cog toward achieving the types of communities that rank high is positive economic, environmental and social metrics along with an attractive and safe pedestrian and bicycle environments and robust transit systems. Indeed transit needs highly walkable and bicycable communities to thrive and car sharing further enhances that by providing individuals with the mobility and accessibility of an auto when the other three modes are insufficient without being encumbered with the high cost of owning a vehicle. The evidence so far is that car sharing reduces the need for vehicles and increases walking, bicycling and transit use.

Reducing the percentage of land devoted exclusively to the auto should be a major priority. This is true in communities of all sizes. The combination of highly walkable and bicycable communities with robust transit systems and car sharing can move us in this direction. It appears that this is what more and more people want and with less pavement for autos we can have more local food production, access to more parks and open space, broader housing choices close to jobs and other amenities and support healthier life styles with more physical activity and social interaction.

Self driving cars don’t have to lead to isolation, sprawl and the demise of transit. They don’t have to be a threat to walking or bicycling. Although these were the thoughts that kept going through my mind at the APTA Conference until I read Jarrett’s post. If we can accommodate twice as many cars on a freeway with self driving cars lets shrink the freeway in half. If the cost of using a self driving car – whether in a car share arrangement or through new pricing mechanisms for all drivers – whether the person pays by the mile or hour then self-driving cars are not likely to be sprawl inducing and walking, bicycling and transit would still be attractive alternatives. However to go back into pessimistic mode while the mix a car sharing and self-driving cars could theoretically significantly shrink roadways and reduce the need for parking, it is hard to envision the politics needed to achieve this end.

Here’s what I think will really happen. Technology rarely has the exact impact that its boosters envision. Edison thought his light bulb would eliminate the need for sleep and I am still waiting for all that extra leisure time that computers were supposed to provide me. I can picture in my head an old Popular Science cover from the 40’s that envisioned a world where we would have personal helicopters. Actually this cover is very relevant to this discussion- there were only a few helicopters in the sky. Can you imagine what our skies would be like if we all had personal helicopters?

The self-driving car boosters envision a world that mixes car sharing with vehicles that can navigate streets without a driver. Up to now automated transportation systems operate on a fixed guideway monitored from a central control point. At what point will self-driving cars be allowed to operate without a licensed driver in position to manually operate the vehicle? I have no idea but anticipate that it will be much longer than self-driving car supporters envision. We are not capable of designing 100% foolproof systems.

Self-driving cars will take away one competitive advantage of transit. Even if a licensed driver must sit behind the wheel he or she can read, text and do the other things possible while riding a bus or train not currently possible while driving. On the other hand, if the cost of using a private vehicle reflects the actual cost of the urban space that it consumes (via a charge by the mile or hour) then walking, bicycling and transit will still be attractive alternatives. Regardless of who is driving, transit vehicles will still use urban space more efficiently than cars do, except in the lowest-demand areas.

I don’t foresee an end to peaking in travel, either by time of day or in busy corridors. This means the idea of constantly circulating vehicles will either increase vehicle miles travelled, as they circulate around empty, or create the need for added parking capacity in areas that have high transit market share. For example, here in Eugene there is virtually no parking at the University of Oregon, while Lane Community College has 4,000 parking spaces to serve a student enrolment of 15,000 plus staff and faculty. Right now there are waves of students going to the colleges for a few hours in the morning (the robo cars would have to circulate empty between the waves), then a few hours when demand drops (need to find parking facilities that do not now exist), and then a few hours of waves away from campus (a reverse of the morning).

My biggest fear is that self-driving cars and robo cars such as driverless taxis will become an excuse for not investing in transit. There is precedent for this. Both in Marin County and in Honolulu plans for rail projects were stopped about 20 years ago when a key policy board was convinced that it would have been more cost effective to purchase every household a person computer that could be used for dynamic ridesharing. Both rail lines are finally under construction 20 years later at much higher costs; the computers were never purchased and although there are now apps that enable dynamic ridesharing, it is clear to all that they are not substitutes for transit.

The busy corridors that can support some form of fixed guideway transport – be it BRT, streetcar, LRT, HRT or commuter or regional rail — will still need these modes regardless how self-driving cars and robo cars develop. I will not be surprised if it is decades before self-driving cars are allowed to operate in mixed traffic without a licensed driver – so the day when transit systems can deploy robo vehicles for first and last mile travel and reduce low producing bus routes will be after few cycles of bus purchases (heavy duty buses have a 12 year life, lighter duty buses 5 to 7 years.)

Self-driving cars will happen but how they shape society is unclear. We need to be vigilant and do what we can to shape this development towards positive ends and away from negative ones. Even with self-driving cars, the limitations of urban space will require us to sustain robust transit systems.

Note: This old post is still useful whenever you see a "driverless cars will change everything" story, (this one, for example) and especially a "driverless cars will be the end of transit" story. Abstract: The two fallacies to watch for in these stories are (a) the "complete imagined future" mode, which denies the problems associated with evolving the future condition instead of just jumping to it, and (b) the assumption, universal in techno-marketing but always untrue in the real world, that when the whizbang new thing appears, everything else will still be the same; i.e. that none if the whizbang thing's imagined competitors will also have transformed themselves. This latter assumption can also be called the "everyone but me is a dinosaur" trope.

Richard Gilbert, co-author of a book that I've praised called Transport Revolutions, has a Globe and Mail series arguing for how driverless cars will change everything. I will give this series a more thorough read, but just want to call out one key rhetorical move that needs to be noticed in all these discussions. It's in the beginning of Part 4, "Why driverless cars will trump transit rivals."

With widespread use of driverless cars – mostly as autonomous taxicabs (ATs) – there could be more vehicles on the road because ATs will substitute for most, and perhaps eventually all, private automobile use as well as much use of buses and other conventional transit.

This, and much of the discussion around driverless cars, is in the complete imagined future mode. Gilbert describes a world in which the driverless cars are already the dominant mode, and where our cities, infrastructure, and cultural expectations have already been reorganized around their potential and needs.

Some complete imagined futures are not necessarily achievable, because the future must be evolved. In fact, the evolution of organisms is a fairly apt metaphor for how cities and infrastructure change. As in evolution, each incremental state in the transformation to the new reality must itself be a viable system. We can think of lots of wonderful futures that would be internally consistent but for which there is no credible path from here to there.

Driverless cars remind me a bit of the "wheeled animal" question in evolution. No animals have evolved with wheels, despite the splendid advantages that wheels might confer on open ground. That's because there's no credible intermediate state where some part of an animal has mutated something vaguely wheel-like that incrementally improves its locomotion to the point of conferring an advantage. Wheels (and axles) have to exist completely before they are useful at all, which is why wheeled animals, if they existed, would be an argument for "intelligent design."

I will begin to take driverless cars seriously when I see credible narratives about all the intermediate states of their evolution, and how each will be an improvement that is both technically and culturally embraced. How will driverless and conventional cars mix in roads where the needs of conventional cars still dominate the politics of road design? How will they come to triumph in this situation? How does the driverless taxi business model work before the taxis are abundant? Some of the questions seem menial but really are profound: When a driverless car is at fault in the accident, to what human being does that fault attach? The programmer? What degree of perfection is needed for software that will be trusted to protect not just the passengers, but everyone on the street who is involuntarily in the presence of such a machine?

Here's a practical example: In Part 3, Gilbert tells us that with narrower driverless cars, "three vehicles will fit across two lanes." Presumably lanes will someday be restriped to match this reality, but when you do that, how do existing-width cars adapt? If you could fit two driverless cars into one existing lane, you could imagine driverless cars fitting into existing lanes side by side, so that the street could gradually evolve from, say, two wide lanes to four narrow ones. But converting two lanes to three narrow ones is much trickier. I'd like to see how each stage in the evolution is supposed to work, both technically and culturally.

That's one reason that I seem unable to join the driverless car bandwagon just yet. The other is that claims for driverless taxis replacing transit amount to imaging a completed new technology out-competing an existing unimproved technology — as though that would actually happen.

Sure, driverless taxis might replace many lower-ridership bus lines, but wouldn't buses become driverless at the same time? In such a future, wouldn't any fair pricing make these driverless buses much cheaper to use where volumes are high? Wouldn't there be a future of shared vehicles of various sizes, many engaged in what we would recognize as public transit? As with all things PRT, I notice a frequent slipperiness in explanations of it; I'm not sure, at each moment, whether we're talking about something that prevents you from having to ride with strangers (the core pitch of "Personal" rapid transit) as opposed to just a more efficient means of providing public transit, i.e. a service that welcomes the need to ride with strangers as the key to its efficient use of both money and space.

If you’ve seen much of Vancouver on television the last few days, you’ve probably seen a shot of a small train gliding along an elevated guideway. It’s SkyTrain, the world’s largest system of fully automated (driverless) metros. Perhaps you’ve ridden driverless trains that shuttle between airport terminals. SkyTrain is the same principle, at a citywide scale.

Driverless trains raise all kinds of anxieties. Many people like knowing there’s someone in charge on the vehicle, and imagine that this person will be useful in emergencies. But on most subways, you can only talk to this person by pushing an intercom button. There’s very little he can do if there’s an emergency in your car other than call for help. Continue Reading →

The Author

Since 1991 I've been a consulting transit planner, helping to design transit networks and policies for a huge range of communities. My goal here is to start conversations about how transit works, and how we can use it to create better cities and towns. Read more.